Welding apparatus for conveyor belts and method

ABSTRACT

A belt welding apparatus is provided for joining together the ends of one or more monolithic conveyor belts. In one form, a belt support is configured to support the belt ends in spaced relation to each other and a non-contact heating device is provided for being disposed between the belt ends to generate thermal radiation for joining the belt ends together. In another form, a drive mechanism is operable to cause relative movement of a pair of platens, for supporting belt ends, toward and away from each other and a heating device between heating and stowed positions. An actuator of the drive mechanism is movable by an operator between at least three operation positions corresponding to three different operation positions of the platens.

CROSS REFERENCES TO RELATED APPLICATIONS

This patent claims benefit under 35 U.S.C. §119 (e) to U.S. ProvisionalApplication No. 61/244,872 entitled “Infrared Vulcanizing Tool forMonolithic Belts” filed Sep. 22, 2009, the contents of which areincorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The invention relates to an apparatus for joining together ends of oneor more conveyor belts and, more particularly, to a welding apparatusfor forming a weld between the ends of one or more monolithic conveyorbelts.

BACKGROUND OF THE INVENTION

Several industries utilize conveyor and process belts for transportingloads from one location to another location or for passing loads throughsuccessive processing operations. Many of these applications requireconveyor belts that are able to maintain cleanliness under various andsometimes harsh conditions. For example, in the food and dairyindustries, conveyor belts should provide sanitary surfaces forconveying food and dairy products to minimize the potential forcontaminating these products. To meet this need, conveyor belt surfacesare often formed of materials, for example thermoplastic materials, thatdo not become easily contaminated when contacted with food or dairyproducts on the conveyor belt surface.

Monolithic conveyor belts are often used in applications that requirelight to medium duty conveyor belts. Unlike traditional conveyor beltsthat include layers or plies of fabric carcasses embedded betweenthermoplastic or rubber layers, monolithic conveyor belts are typicallyformed from a single homogenous material, for example a thermoplasticmaterial, although they may include other composite materials such asreinforcing fibers. Forming the belt from a single thermoplasticmaterial is often desirable because the thermoplastic material is lessprone to providing sites for microbiological growth due to contaminationfrom, for example, contact with conveyed food or dairy products.However, because these monolithic conveyor belts do not include a fabriccarcass to increase the tensile strength of the belt, it is particularlyimportant to ensure that these belts possess a generally uniform crosssectional thickness, and do not have areas of weakness where tearpropagation can occur, potentially leading to ultimate failure of thebelt.

In addition, monolithic conveyor belts used in these applications canoften take the form of positive drive belts. Like monolithic beltsgenerally, as described previously, monolithic positive drive belts areformed of a homogeneous thermoplastic material, with or without theaddition of reinforcing materials. However, these belts additionallyinclude projections that are configured to interengage with structureson a drive roller to positively drive the projections to drive theconveyor belt. In one example, these belts include a series of equallylongitudinally spaced, laterally extending drive projections or finsthat extend generally orthogonally from the non-conveying surface of thebelt. Unlike ordinary conveyor belts, which typically rely on frictionbetween the belt and drive rollers in the conveyor system to provide thedriving force to move the conveyor belt, positive drive belts utilizeforce generated on a driving side of the ribs, in addition to frictionalforces, to generate the driving force to drive the belt. To this end, aconveyor system utilizing monolithic positive drive belts will typicallyinclude one or more driven rotatable sprockets that interengage with theribs, so that upon rotation of the sprockets, the sprocket teeth willengage the driving side of the ribs to generate the driving force in theconveying direction of the conveyor belt system. Similarly, the positivedrive belt may include cogs that are positively driven by a driveroller. Thus, monolithic positive drive belts typically have a uniformpitch, which is the longitudinal distance between the projections, e.g.the crests of the ribs along the belt, which corresponds to a uniformcircular pitch of the sprocket being used to drive the belt.

During installation and repair of monolithic belts, including bothstandard and positive drive belts, it is often necessary to jointogether the ends of one or more monolithic conveyor belts. Whileseveral methods exist for joining together the belt ends, includingutilizing adhesives or mechanical fasteners to join the ends, onepreferred method is to form a butt weld between the belt ends. To thisend, the belt ends are typically prepared by squaring the belt ends sothat they extend orthogonally to the belt edges, although they may beformed at corresponding angles to one another. The prepared belt endsare heated to soften or melt the material at the belt ends. With thematerial in the belt ends remaining softened, the belt ends aresubsequently urged together into end-to-end abutment so that thematerial of the two belt ends becomes intermixed. Upon subsequentcooling of the belt ends, the softened material of the two belt endswill harden and fuse to join the belt ends together.

Previous conveyor belt welders have generally included a pair oflongitudinally extending belt positioning platens positionedside-by-side, with at least one of the platens translatable toward andaway from the other platen. In this regard, it should be noted that thiswelder extends lengthwise across the lateral or transverse width of thebelt so that the transverse center of the tool is generally disposed atthe longitudinal ends of the belt or belts to be joined together.

The top surfaces of the platens are generally coplanar, and the beltends are positioned on the platens, and held in place, so that uponlateral movement of one of the platens toward the other of the platens,the belt ends will engage to facilitate intermixing of the material ofthe belt ends. In the previous welders, a lever is connected to a shaftand configured so that rotation of the lever and the shaft generatestransverse movement of one of the platens. A rack and pinion gear isused to translate the rotation of the shaft into transverse movement ofthe movable platen toward and away from the stationary platen.

In the prior welding apparatus, a contact heating element is positionedbetween the belt ends during heating, and the belt ends are moved intoengagement with the contact heating element to melt the belt ends. Theheating element includes an elongate contact heating bar or wand thathas a pair of heated surfaces, on each side of an elongate bar with agenerally rectangular cross section. A resistance heating element runsthrough the heating bar to heat the bar to a welding temperature. Theheating bar is formed of a heat conducting material, for example a metalmaterial, to conduct heat from the resistance heating element, to theouter heated surfaces of the heating bar. The heated surfaces face thebelt ends to be welded together which are shifted to engage the heatedsurfaces for melting the belt material at the belt edges. Due toconsiderable material loss due to sticking of the belt material to theheated surfaces of the heating element, a non-stick material, forexample Teflon, is coated on the heated surfaces to reduce the amount ofmaterial that sticks to the heating bar during contact heating of thebelt ends.

In the prior welder, a handle is disposed at the top of the heating bar,to provide a location for a user to grasp and lift the heated bar fromabove in order to insert and remove the heated bar from its weldingposition between the belt ends. The handle is typically formed with aheat insulating cover to help protect operators from injuring themselveson the heated bar. The prior belt welder provides a space between theplatens, between which the heated bar may be manually inserted andremoved from above during welding.

Prior to use, the belt ends are typically prepared by cutting to formbelt edges that are substantially perpendicular to the belt longitudinalor lengthwise direction. Next the belt ends are loaded on the platens.To this end, the user can rotate the handle, which causes the shaft torotate, so that the pinion urges the rack laterally to move one of theplatens toward and away from the other platen. To position the belt endsin a starting position, the user rotates the lever clockwise to spacethe platens apart. The user next places a separate spacer between theplatens and rotates the lever in the opposite counter-clockwisedirection to move the platen back toward the other platen to squeeze theplatens against the spacer. The belt ends are next positioned on theplaten upper surfaces. If the welder is being used to join positivedrive belts ends, separate adapters must be utilized to key the ribs.The belt ends are clamped into position on the platen upper surfaces,with the belt ends positioned in end-to-end abutment, and the spacer isremoved.

With the belt ends mounted, the user may next heat the belt ends byfirst rotating the lever clockwise to slide the movable platen away fromthe opposite platen, providing a space between the two belt ends. Withthe belt ends separated, the user must grasp the upper handle of thepreviously preheated heating bar, and manually lower the heating barinto the space between the belt ends. With the heating bar between thebelt ends, the lever is rotated in the opposite counter-clockwisedirection in order to move the movable platen back toward the oppositeplaten so that each belt end abuts a corresponding one of the heatedsurfaces of the heating bar to squeeze the heating bar between the beltends. In the prior welder, the user visually determines the properextent that the belt ends are moved against the heating bar and theamount of time that the belt edges are pressed against the heating barby subjectively determining whether a sufficient mushroom shape ofmelted material has been extruded from between the belt ends and theheating bar. Thus, the user must determine, typically based onexperience, the amount of time to leave the belt ends in engagement withthe heated bar. The amount of time will generally depend on thecharacteristics of the belt, including its cross sectional size and thematerial from which it is made, as well as the temperature of the heatedbar. It should be noted that the material that is extruded from the beltends during heating is not used to join the belt ends and must beremoved. This can lead to inconsistent results welds because the extentof the mushroom of Material is subjectively determined by the operator.This is particularly problematic in positive drive belts, because withvarying amounts of extruded material, either the pitch will changebetween the adjacent ribs during joining of the belt ends or the amountof belt material at the joint will vary, leading to thinner areas of thebelt with insufficient belt material and areas of weakness.

After the user has determined that the ends of the belt are sufficientlysoftened to form a weld therebetween, i.e. a sufficient mushroom of beltmaterial has formed at the interface with the heating bar, the user mustagain rotate the handle in the clockwise direction to move the movableplaten away from the stationary platen to provide clearance for removingthe heated bar. With the belt ends separated the user again grasps theupper handle of the heating bar and lifts it from between the belts.While the belt ends are still softened, the user next rotates the handleback in the counter-clockwise direction so that the rack and pinion urgethe movable platen toward the stationary platen to clash the belt endsagainst one another to overlap their softened material. In thesesystems, because it is important to quickly join the belt ends afterthey have been heated, the time required for the operator to remove theheating device has been found to reduce the quality of the resultingwelds because the belt ends are given time to cool.

After the heating device is removed, the handle is rotated beyond theposition at which the belts were loaded so that the belt ends overlappast their original position of end-to-end abutment and the softenedmaterial of the belts can intermix. In this regard, a portion of themelted material will be extruded from between the belt ends, forming amushroom of material about the joint area. The extent that an operatormoves the handle past the original end-to-end abutment with the priorwelder is determined by the amount of material that extrudes out frombetween the belts, a subjective standard that does not provideconsistent belt overlap distances from welding operation to weldingoperation, reducing the repeatability and quality of belt splices. Itshould be understood that at this point, the longitudinal lengths of thebelt ends will be effectively decreased by a combined amount equal tothe distance that the belt ends are overlapped beyond their originalend-to-end abutment position. The belts are held in this position untilthe material between the belt ends is sufficiently cooled, to reharden,fusing the material of the two belt ends together and forming a jointbetween the two belt ends.

A high quality weld results in a joint between the belt ends thatclosely resembles the original belt in both material strength and sizewhile also providing a continuous conveying surface. In contrast, poorlyformed welds can result in bubbles forming in the material at thewelding site due to overheating, potentially resulting indiscontinuities in the belt surface providing locations formicrobiological growth when contaminated and also areas of weaknesswhere tear propagation and ultimate failure of the belt can occur. Poorwelds can form for several reasons. For example, if the belt is heatedat too high a temperature or for too long, the material at the very edgeof the belt can become burned or overheated, changing the chemicalcomposition of the material and potentially forming an area of weaknessand discoloration of the belt and porous bubbles to form. If the beltends are heated at too low of a temperature or for too short a period oftime, the belt ends may not be sufficiently melted to intermix with thematerial of the opposite belt end to sufficiently fuse together to forma joint between the belts upon subsequent cooling.

Several problems have been found to exist with the prior welding toolthat decrease the quality of welds produced with these tools. First, ithas been found that during heating, with the belt ends contacting theresistive heating device, despite the non-stick coating on the heatingbar, at least a portion of the heated material sticks to the heatingelement when the belts are removed. In addition, upon inserting andremoving the heating element within the space between the belt ends, theoperator often unintentionally contacts a portion of the heating elementagainst a portion of the belt end, causing further material loss andnon-uniform heating to the belt ends. Material sticking to the heatingdevice is inconvenient to users and requires regular manual cleaning ofthe heating device between each welding operation. Material loss is alsoproblematic, particularly if the welding tool is used to weld togetherends of a positive drive belt. In this regard, it is difficult tomaintain the pitch between ribs adjacent to the weld site, because anunknown quantity of the belt material is removed from the belt ends.Because the amount of overlap of the belt ends is determined by visuallyexamining the extruded belt material between the belt ends as they areengaged, the extent to which the belts overlap to generate this materialextrusion will vary with the amount of material lost during beltheating, decreasing the user's ability to obtain repeatable belt weldingresults and maintain the proper pitch between ribs of the belt. Becausepositive drive belts and the sprockets that drive them have precisecorresponding pitches, altering the pitch between two ribs where thebelt ends are joined together can interfere with proper functioning ofthe positive drive system. It has also been found that the edges of thebelt ends contacting the heating element can become damaged or scorchedduring heating, degrading the quality of the final weld as describedpreviously.

The prior welder can also lead to uneven belt heating and non-uniformbelt joining results. More specifically, uneven heating can be caused ifthe heating element does not have a consistent temperature along theentire width of the conveyor belt ends so that hot and cool portions areformed with some material being subjected to more heat along the widthof the conveyor belt. This can result in portions of the belt widthbecoming overheated or underheated, which may result in a deficient weldas described previously. In addition, it has been found that the priorwelder leads to unrepeatable results due to the heating depth along thebelt varying upon the user engaging the belt ends against the heatingelement. Specifically, determining that a proper mushroom shape ofextruded material has formed between the belt ends and the heater toassess adequate heating is an imprecise measure and may vary fromoperator to operator and from weld to weld.

In the same manner, the extent that the user overlaps or clashes thebelt ends together has been found to vary. During the belt joiningstage, the user clashes the belt together until a proper “bead” ofmaterial forms at the interface between the belt ends at upper and lowersurfaces thereof. However, determining the proper clash based on a beadof material forming is very subjective and makes it difficult foroperators to generate repeatable results with consistent pitches of theresulting belt. In addition, the welding operation requires precision,with an amount of material clash on the order of one millimeter, so thatit is difficult for an operator to provide the precise amount ofrotation of the handle without moving the handle too much or too little,which can create a weaker weld because the material being clashed withthe opposite belt end may be further from the edges of the belts, whichmay not be full melted, so that the resulting weld may be weak. Creatingthe wrong amount of overlap between the belt ends not only forms a weakweld between the belt ends but can also lead to an incorrect pitchbetween the ribs on a positive drive belt, decreasing its ability toproperly operate in a positive drive system.

At the same time, the prior welder can be relatively unsafe andinconvenient because it requires the operator to rotate the handle withone hand while manually inserting and removing an extremely hot heatingbar between the belt ends and an additional spacer. The operator musttherefore go through a number of discrete steps and maintain the heatingelement outside of the tool for a substantial portion of the weldingoperation. In addition, the resistance heating elements used in thistool must be preheated for a relatively long period of time prior toreaching a desired weld temperature, and similarly must be cooled for arelatively long period of time, so that the cycle time for creating aweld can be long.

SUMMARY OF THE INVENTION

The present belt welding apparatus for joining two ends of one or moremonolithic conveyor belts provides consistent heating and joining of theends of one or more conveyor belts. Herein, it will be understood theterm belt ends contemplates portions of a belt or belts at the endsthereof. Further, the term monolithic conveyor belt includes conveyorbelts having additional composite materials. In accordance with oneaspect, the present belt welding apparatus includes a belt support forsupporting the belt ends in spaced relation to each other and anon-contact heating device for being disposed between and spaced fromthe belt ends for generating thermal radiation to provide to the beltends so that the belt ends can be welded together. In this regard, thenon-contact heating device generates thermal radiation sufficient tomelt the material of the belt ends without contacting the belt ends sothat belt material does not stick to the heating device and the heatingdevice does not have to be cleaned between welding operations.Similarly, the use of a non-contact heater also reduces material lossfrom the belt ends due to sticking. In this manner a uniform pitchbetween drive projections in a positive drive belt may be maintainedwithout reducing the amount of material or thickness of the conveyorbelt at the weld location so that a strong resulting weld may be formed.It has been found that using a non-contact heating device providesthermal radiation to more uniformly heat the belt ends without scorchingor damaging the belt material than engaging the belt ends against aheating device until a sufficient mushroom of material is extrudedtherefrom. It should be understood that the term melt, as used herein,generally refers to heating the belt material to sufficiently soften thebelt material for joining the belt ends together. Melting of the beltmaterial does not necessarily mean that the belt material becomes moltenso that it drips from the belt ends, but includes belt material thatretains viscosity and does not drip.

In one form, the non-contact heating device includes an infrared heatingdevice that is disposed between the two ends of one or more monolithicconveyor belts and spaced therefrom. The infrared heating device iscapable of rapidly heating to avoid the need for an operator to wait fora resistance heating bar to preheat prior to heating the belt ends,reducing the cycle time of the welding apparatus.

The belt support may include a pair of platens wherein one of theplatens has a movable mount. The non-contact heating device also has amovable mount, and an actuator is operable to simultaneously shift themovable mount for the one platen in a belt shifting direction and themovable mount of the non-contact heating device in a heating deviceshifting direction that is transverse to the belt shifting direction. Inone form, the belt shifting direction is orthogonal to the heatingdevice direction. In this manner, an operator can conveniently shift theplatens, and the belt ends supported thereon, and the heating devicewith an actuator and avoid the need for utilizing a separate heating barthat must either be held or placed to the side during welding, as wasrequired with previous belt welding devices.

In one form, the actuator is coupled to both the belt support and thenon-contact heating device and is operable to shift the belt support andnon-contact heating device between a belt loading position, a belt endmelting position, and a belt end joining position, providing convenienceto the operator. In this regard, the belt support is configured tosupport the belt ends closely adjacent to or engaging each other and thenon-contact heating device is configured to be disposed in a stowedlocation in the belt loading positions thereof. In this position, theoperator can easily load the belt ends onto the platens withoutinterference by the heating device. When the actuator is operated toshift the belt support and the non-contact heating device to the beltend melting position, the belt support is configured to support the beltends to be spaced from each other and the non-contact heating device isconfigured to be disposed between the belt ends. Thus, the belt ends areseparated to provide clearance for the heating device and the heatingdevice is moved between the belt ends to melt the material thereof byuse of the actuator to avoid the operator having to separately move thebelt ends apart and manually insert a heating device. The actuatorprovides convenience to the operator and reduces the occurrence ofinadvertent contact of the heating device and the belt ends, which couldotherwise lead to uneven heating of the belt ends and material loss.With the belt support and the non-contact heating device shifted to thebelt joining position by operation of the actuator, the belt support isconfigured to support the belt ends to engage each other and thenon-contact heating device is configured to be disposed in a stowedlocation. In this manner, the non-contact heating device is removed sothat the belt ends can be joined together without requiring the operatorto remove the heating device manually, avoiding inadvertent contact withthe belt ends. In addition, the operator is not required to separate thebelt ends and manually remove a heating bar, which requires additionaltime and could otherwise give the belt ends time to cool and reduce thequality of the resulting weld.

In one form, the belt support includes a pair of platens with structuresfor receiving drive projections of the belt ends: A template configuredfor forming a cut belt ends is provided so that when the driveprojections are received by the platen structures, there is apredetermined spacing between each of the belt ends and the non-contactheating device disposed therebetween. In this regard, the distancebetween the belt ends and the non-contact heating device is consistentso that the belt ends are properly heated without requiring a subjectivevisual identification of belt heating by the operator. In addition,extruded belt material is not formed during belt heating as withprevious welders, which would otherwise reduce the material for formingthe weld, so that consistent welds are formed.

According to another aspect, the welding apparatus includes a drivemechanism that is operable to move a pair of belt supporting platensrelative to each other to move the belt ends toward and away from eachother and to move a heating device between a heating position, with theheating device disposed between the belt ends and a stowed position. Anactuator is coupled to the drive mechanism and can be moved by theoperator between at least three operation positions that correspond todifferent operation positions of the pair of platens. With the actuatorin a belt loading operation position, the platens are spaced from eachother by a predetermined loading distance and the heating device is in astowed position. In this regard, the operator can load conveyor beltends on the platens without interference from the heating device andwithout having to separately manually hold a heating bar or set it offto the side. In a belt heating operation position of the actuator, theheating device is in the heating position and the platens are spaced bya predetermined heating distance from the heating device. With theactuator in a belt joining operation position, the heating device is inthe stowed position and the platens are spaced closer together than thepredetermined loading distance so that the melted belt ends supported onthe platens engage each other and are allowed to solidify to join thebelt ends together. The actuator also allows the operator tosequentially move the belt ends supported by the platens and the heatingdevice into their respective positions corresponding to each of theoperation positions using a single actuator. Providing an actuator forpositioning the heating device between the belt ends or in a stowedposition provides operator convenience, because the operator is notrequired to manually insert and remove a heating device between the beltends. Further, the heating device may be removed without inadvertentcontact with the belt ends so that the proper amount of belt overlap maybe created during belt joining without creating an area of weakness atthe weld location due to insufficient material. In addition, theactuator provides appropriate spacing of the belt ends relative to theheating device so that the belt ends are properly heated for each weldcycle and provide consistent results. In this approach, preferably oneplaten is fixed and the other platen is movable toward and away from thefixed platen, although both platens may be movable.

The actuator may include a rotatable lever that is rotatable along apredetermined arcuate pathway. The actuator belt loading operationposition is an intermediate position of the lever along the pathway. Thebelt heating operation position and the belt joining operation positionare on either side of the intermediate position. In this regard, for acomplete joining cycle, the lever is only shifted in opposite rotarydirections or more particularly, the lever is rotated once in a firstrotary direction from the intermediate position to the belt heatingoperation position and once in a second rotary direction opposite to thefirst rotary direction from the belt heating operation position to thebelt joining operation position. In this regard, with the actuator inthe intermediate position, the operator can conveniently sequentiallymove both the heating device and the belt ends to different operationpositions with only two rotational movements of the lever along thearcuate pathway.

In one form, the actuator is rotatable along a predetermined arcuatepathway and may include a preset intermediate position corresponding tothe actuator belt loading operation position. The actuator belt heatingoperation position and the actuator belt joining operation position areat preset positions in different rotary directions along the pathway atpredetermined angular distances from the preset intermediate position.In this regard, by moving the actuator between the preset positionsalong the arcuate pathway, the operator can move the heating device andthe platens to their different operation positions in appropriaterelation to each other consistently during each belt joining operationto provide proper heating and joining of the belt ends.

In one form, the welding apparatus includes a housing assembly, and theplatens, the drive mechanism and the actuator are mounted to thehousing. A detent mechanism is included between the housing assembly andthe drive mechanism, and releasably retains the actuator in theintermediate position to define the intermediate position. Preferably,the drive mechanism includes stops to define preset positions of theactuator at the belt heating operation position and the belt joiningoperation position. The stops advantageously provide the operator with apositive indication of the belt heating operation position and the beltjoining operation position of the actuator so that proper heating andjoining of the belt ends can be consistently achieved.

The welding apparatus may be used with positive drive belts having driveprojections projecting therefrom that are arranged so that adjacentdrive projections having a predetermined pitch spacing therebetween. Inthis regard, the actuator belt joining operation position includes apreset position of the actuator with the platens spaced by apredetermined joining distance that is a predetermined distance lessthan the predetermined loading distance. In this regard, the belt endsare brought together to overlap each other by a predetermined amountthat is equal to at least the predetermined distance so that the beltmaterial can intermix and the endmost drive projections of the joinedbelt ends retain the predetermined pitch spacing thereof, while avoidingthe operator having to subjectively determine the appropriate amount ofbelt overlap so that the pitch could vary, as with previous belt weldingdevices. A template may be configured to cut the belt ends so that withthe drive projections received in the platen structures and the actuatorin the belt loading operation position, the belt ends abut each other.With the actuator moved to the belt joining operation position, theoverlap of the melted belt ends is equal to the predetermined distance.In this manner, the configurations of the template and plates arecoordinated to provide a predetermined amount of material of the beltends beyond the drive projections after a cut is made, so that thewelding apparatus can obtain repeatable results and maintain properpitch between adjacent drive projections of the belt.

In one form, the drive mechanism of the welding apparatus includes a cammechanism that has a cam path that is shifted by operation of theactuator. Cam followers are connected to the heating device and one ofthe platens and mounted in the cam path so that actuator operationgenerates caroming action between the cam path and the cam followers forshifting the heating device and the platen connected thereto. The campath can have a predetermined configuration programmed so that as theactuator is shifted between the belt loading position and the beltjoining position, the heating device remains substantially stationary inthe stowed position. In this regard, the cam mechanism advantageouslygenerates programmed movement of both the platen and the heating device.

According to another aspect of the invention, a method for weldingconveyor belt ends together is provides that includes supporting thebelt ends in spaced relation from each other. The method also includesmelting the material of the belt ends by operation of a heating devicetherebeween. Further the method includes providing a single actuator tosequentially shift the heating device and the belt ends by operating thesingle actuator to shift the heating device into the space between thebelt ends, operating the single actuator to shift the heating device outfrom the space between the belt ends after the material of the belt endsis melted, and operating the single actuator to shift the belt endstoward each other to intermix the melted material. In this regard, anoperator can operate the single actuator for a welding operation thatjoins the belt ends together. In this manner, an operator canconveniently join belt ends together using a single actuator andavoiding the need to manually insert and remove a heated bar frombetween the belt ends. In one form, the single actuator sequentiallyshifts the heating device and the belt ends by rotating the singleactuator only once in opposite rotary directions, providing a consistentmethod for positioning the belt ends and the heating device.

According to another aspect of the invention, a heating device formelting belt ends is provided that includes a tubular thermal radiationtransmissive housing with a heating filament extending therein. &thermalradiation reflective coating extends about and along the tubularhousing. Uncoated opposite side portions allow thermal radiation to passtherethough toward belt ends adjacent to the uncoated portions, whilethe reflective coating restricts thermal radiation transfer therethough.In this manner, thermal radiation is directed toward the belt ends andnot in undesired directions. In one form, the heating filament is closerto a bottom portion than to a top portion of a generally cylindricalchamber of the housing and the uncoated portions are closer to thebottom portion so that they are aligned with the heating filament. Inthis manner, the amount of heat direct toward the belt ends adjacent tothe uncoated portions is maximized.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a belt welding apparatus in accordancewith one aspect showing an actuator lever positioned in a belt joiningoperation position;

FIG. 2 is a perspective view of the belt welding apparatus of FIG. 1showing the lever positioned in a belt joining operation position andshowing in phantom different operation positions of the lever;

FIG. 3 is a perspective view of an end plate;

FIG. 4 is a perspective view of a cam disc having a generally U-shapedcam cutout.

FIG. 5 is a perspective view of one end portion of the belt weldingapparatus of FIG. 1 showing the location of the cam followers in the campath when the lever is in the belt loading operation position;

FIG. 6 is similar to the perspective view of FIG. 5 showing the locationof the cam followers when the lever is in the belt heating operationposition;

FIG. 7 is similar to the perspective view of FIG. 5 showing the locationof the cam followers when the lever is in the belt joining operationposition;

FIG. 8 is a cross-sectional view taken along line A-A of FIG. 1 showingthe heating element in a lowered stowed position and the platens in abelt loading configuration relative to each other;

FIG. 9 is a cross-sectional view similar to FIG. 8 showing the heatingelement in a raised heating position and the platens spaced apart in aheating configuration relative to each other;

FIG. 10 is a cross-sectional view similar to FIG. 8 showing the heatingelement in a lowered stowed position and the platens in a belt joiningconfiguration relative to each other;

FIG. 11 is a cross-sectional perspective view of a heating device of thebelt welder; and

FIG. 12 is perspective view of a positive drive conveyor belt cuttingtemplate for cutting ends of positive drive belts to be joined with thepresent welding apparatus; and

FIG. 13 is a perspective view of a welding apparatus according toanother approach with the frame removed showing a heating deviceaccording to another approach.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIGS. 1 and 2 a belt welding apparatus 5 in accordance with one formis illustrated, which includes a belt support 6 for positioning the ends35 and 40 of one or more conveyor belts (FIG. 3) in spaced relation fromeach other and a heating device 70 for being disposed between the beltends 35 and 40 for melting a portion of the material thereof. The beltsupport 6 may include a pair of elongate platens 10 and 15 extendingside-by-side in a lengthwise direction across the lateral width of thebelt ends 35 and 40 for supporting the belt ends thereabove. At leastone of the platens 10 is preferably movable laterally with respect tothe other platen 15 for moving one of the belt ends 35 toward and awayfrom the other belt end 40. The belt positioning platens 10 and 15, andparticularly upper surfaces 25 and 30 thereof, are substantiallyhorizontal and coplanar with one another. In this respect, the conveyorbelt ends 35 and 40 can be loaded on the upper surfaces 25 and 30 of thepositioning platens 10 and 15 when the platens are in a loadingconfiguration, illustrated in FIGS. 5 and 8, such that the belt ends 35and 40 are positioned in end-to-end relationship thereon. The platens 10and 15 can be used to support the ends of one or more monolithic orpositive drive conveyor belts 35 and 40 (shown), as well as other typesof conveyor belt ends. With the belt ends 35 and 40 supported on uppersurfaces 25 and 30 of the platens 10 and 15, clamping members 42 areprovided for clamping the belt ends 35 and 40 against the upper platensurfaces 25 and 30. The clamping members 42 in the form of clamp bars 45and 50 are positioned above the belt ends 35 and 40, respectively, andare tightly clamped to the upper platen surfaces 25 and 30 to tightlyclamp the belt ends 35 and 40 therebetween to restrict movement of thebelt ends 35 and 40 relative to the platens 10 and 15, respectively,during operation of the belt welding apparatus 5. In this regard, itshould be noted that the belt welding apparatus 5 extends in alengthwise direction across the lateral width of the belt so that thetransverse center of the tool is disposed at the longitudinal ends 35and 40 of the belt or belts to be joined together.

Turning to FIGS. 8, 11, and 13, a heating device 70 extends in thelengthwise direction of the belt welding apparatus 5 and is movablymounted at each end thereof to a frame housing 140 and is movablebetween a raised heating position 71 (FIGS. 6 and 9), wherein theheating device 70 is disposed between the conveyor belt ends 35 and 40and a lowered stowed position 72 (FIGS. 5 and 8), wherein the heatingdevice 70 is removed from between the conveyor belt ends 35 and 40 sothat the belt ends can be moved toward each other without interferenceby the heating device 70. In one form, in the stowed position, theheating device 70 is in a lowered stowed position within the framehousing 140, where the top portion 73 of the heating device 70 ispositioned vertically below the bottom surfaces of the platens 10 and 15so that the platens can be positioned over and substantially cover theheating device 70 in its stowed position. In the heating position withthe platens 10 and 15 laterally spaced apart to provide clearance forthe heating device 70, the heating device 70 is vertically raised sothat the heating device 70 is positioned in a gap 80 formed between theplatens 10 and 15 and is generally horizontally aligned with the beltends 35 and 40. In this manner, the heating device 70 can be used toprovide thermal radiation to the conveyor belt ends 35 and 40 to melt aportion of the material thereof. Melting of the belt material is usedherein to refer to sufficient heating of the material so that thematerial is softened and capable of forming a weld or join between theconveyor belt ends. In one form, the heating device 70 includes anon-contact heater 75 and is laterally offset from the edges 85 and 90of the belt ends 35 and 40 by a predetermined distance to provide a gaptherebetween. The gap is sufficient to allow adequate thermal radiationtransfer between the heater 75 and the belt edge portions 85 and 90 toadequately heat and melt the material at the belt edge portions 85 and90, but to not overheat or burn the belt edges. In this regard, precisepositioning of the heater 75 relative to the belt edge portions 85 and90 can be controlled with a drive mechanism 210 described in more detailbelow. So configured, during heating, the belt ends 35 and 40 do notcontact the surface of the non-contact heater 75 and instead thenon-contact heater 75 emits thermal radiation across the gap to heatedge portions 85 and 90 of belt ends 35 and 40, thus preventing the lossof material therefrom that may otherwise occur due to sticking to theheater 75.

The platens 10 and 15 are also movable between different positionsrelative to each other, including a belt loading position 86 (FIG. 8) abelt heating or melting position 87 (FIG. 9), and a belt joiningposition 88 (FIG. 10). In the belt joining position 88 the platens 10and 15 are positioned closer laterally to each other than in the loadingposition 86 thereof, by a predetermined amount. In this manner, when theplatens are moved to the joining position 88 the belt ends 35 and 40,and more particularly the edge portions 85 and 90 thereof, are urgedtoward one another by a predetermined distance beyond their originalend-to-end arrangement so that the softened edge portions 85 and 90clash together to overlap the belt ends 35 and 40 by a predeterminedamount equal to the predetermined distance. The belts are preferably inend-to-end abutment in the loading position so that the distance theplatens 10 and 15 move toward one another is equal to the belt overlapor clash when the belts are shifted to the belt joining position,however, the belt ends may be spaced in the loading position so that theamount of overlap is less than the amount the belt ends are shiftedtoward each other. For example, the predetermined amount may be betweenabout 0.5 and about 2 mm. In one form, the predetermined amount is about1.0 mm. Thus, after heating of the belt edge portions 85 and 90 tosufficiently melt the material, the melted material in the belt ends 35and 40 intermixes so that upon cooling and hardening of the material,the belt ends 35 and 40 become fused to one another and their combinedlength is reduced by the predetermined amount.

The belt welding apparatus 5 includes a drive mechanism 210 for drivingat least one of the platens 10 toward and away from the other platen 15to move the platen 10 between the different operation positions thereof.The drive mechanism is also provided for shifting the heating device 70between the raised heating position 71 and the lowered stowed position72. A common drive mechanism 210 may be used for moving both the oneplaten 10 and the heating device 70, or separate drive mechanisms may beused. In one form, the drive mechanism includes a cam drive mechanism211 for driving both the one platen 10 and the heating device 70 betweendifferent operation positions. A user operable actuator 94 is providedfor operation of the cam drive mechanism 211. In one form, the actuator94 and drive mechanism include a lever 95 disposed on a rotatable camdisc 100 and a drive coupler in the form of a connecting shaft 105securely coupled to the cam disc 100 that extends longitudinally acrossthe belt welding apparatus 5 and is securely coupled to a generallymirror image, second rotatable cam disc 110 positioned on the oppositelongitudinal end so that the shaft causes the second rotatable cam disc110 to generally rotate to the same extent as the first cam disc. Inthis manner opposite cam drive mechanisms 211 may be provided. Thus,upon rotation of the lever 95 using a handle 115 of the actuatorextending therefrom, the cam discs 100 and 110 are rotated bysubstantially similar angles through rotation of the shaft 105.

The cam discs 100 and 110 each include cam cutouts 120 in their innersurfaces 121 that are programmed to provide movement of the movableplaten 10 and the heating device 70 as the lever 95 is rotated. To thisend, a pair of movable platen cam followers 125 and a pair of heatingdevice cam followers 130 are mounted respectively to each longitudinalend of the movable platen 10 and the heating device 70, with the camfollowers 125 and 130 disposed within the cam cutouts 120. Rotation ofthe cam discs 100 and 110 urges the cam followers 125 and 130 to followouter and inner cam surfaces 135 of the cam cutouts 120, which in turnurges the movable platen 10 and the heating device 70 to move along apredetermined path as described in more detail below. In this manner,the movement of the platen 10 and heating device 70 to predeterminedoperative positions is controlled by the movement of a single handle 115by an operator. In one approach, a single cam cutout 120 at eachlongitudinal end of the welding apparatus 5 is used for movement of boththe movable platen 10 and the heating device 70, although more than onecam cutout may be used. If a single cam path is used, the cam followers125 and 130 in this approach may both utilize separate active portions,305 and 345 respectively, but may both share a single common inactiveportion 340.

Turning to more of the details, in one aspect, the belt weldingapparatus 5 includes a housing frame formed of a frame 140 with twolongitudinally extending sidewalls 145 and a longitudinally extendingbottom 150. Endplates 155 and 160 are positioned at each end of theframe 140. So configured, the frame 140 and the end plates 155 and 160generally define an upwardly open heating device housing 165. The beltpositioning platens 10 and 15 are located above the frame 140 and extendlongitudinally between the end plates 155 and 160 to cover at least aportion of the heating device housing 165. The frame 140 may be formedfrom a metal material, including steel or aluminum that is preferablystrong to provide support for the other components of the belt weldingapparatus 5 and lightweight to facilitate portability of the beltwelding apparatus 5.

The end plates 155 and 160 provide structural stability to the beltwelding apparatus 5 and provide a position of mounting of several of thecomponents of the welding apparatus 5. In one aspect, the end plates 155and 160 each include at least one horizontally extending channel 170 onan inner surface 175 thereof that is sized to retain end portions 180 ofthe platens 10 and 15. The horizontal channels 170 are configured toallow lateral movement of the movable platen 10 toward and away from thestationary or fixed platen 15 between the inner welding position and theouter heating position thereof. The stationary platen 15 is alsocaptured within the horizontal channel 170, but is securely attached tothe endplates 155 and 160, so that during operation, the stationaryplate 15 does not move laterally with respect to the belt weldingapparatus 5.

The endplates 155 and 160 additionally include vertical channels 205 forslideably retaining heating device vertical guiderails 185, allowingvertical movement of the heating device 70 between the lowered stowedposition 72 and the raised heating position 71, while restrictinglateral or rotational movement of the heating device 70. A centermounting aperture 186 formed in each of the endplates 155 and 160 isutilized for mounting the two ends 190 of the shaft 105 and to allowrotation of the shaft 105 therein. The end plates 155 and 160additionally includes a pair of cam follower slots 195 and 200 formedthrough each of the end plates 155 and 160 for allowing a portion of therespective cam followers 125 and 130 to pass therethrough and moverelative to the end plates 155 and 160 during movement of the camfollowers 125 and 130.

To this end, the end plates 155 and 160 are preferably formed from arelatively strong material, which provides a smooth low friction surfaceand good abrasion resistance, along with providing relatively strongstructural support to the belt welding apparatus 5, for example acetylor poly-oxymethylene (POM). In this manner, the shaft 105 is easilyrotated by the user within the mounting apertures 186, and the innersurfaces of the mounting apertures 186 do not become quickly worn withuse of the belt welding apparatus. Similarly, forming the end plates 155and 160 of a material with these properties provides good abrasionresistance to minimize wear caused by the lateral movement of themovable platen 10 within the platen channels 170 and from verticalmovement of the heating device guide rails 185 within guide railvertical channels 205, both formed in the inner surfaces 175 of the endplates 155 and 160. It also minimizes wear from the cam followers asthey move within the cam follower slots 195 and 200 formed through, theend plates 155 and 160.

In one aspect, the drive mechanism 210 is configured for moving themovable platen 10 and the heating device 70 between operative positions.In one example, the drive mechanism 210 includes an actuator 94 in theform of a handle 115 disposed on and extending from the lever 95 that isattached to the first end disc 100. As mentioned previously, the shaft105 is coupled to the inner surface 121 of the first rotatable cam disc100 and extends longitudinally across the belt welding apparatus 5 whereit is coupled to the second rotatable cam disc 110 located at theopposite longitudinal end of the belt welding apparatus 5 so that a pairof cam disc drive mechanisms 211 are provided. In this configuration,the lever 95 is rotatable along an arcuate pathway, and rotation of thelever 95 by a particular angle using handle 115 rotates the firstrotatable cam disc 100 by a corresponding angle, which drives the shaftto provide an equal angle of rotation in the second rotatable cam disc110.

In one aspect, each rotatable cam disc 100 and 110 is formed with camcutouts 120 on inner surfaces thereof that are programmed to drivecorresponding platen cam followers 125 and heating device cam followers130 between different operative positions. In this regard, cam followers125 and 130 are coupled to each longitudinal end of the movable platen10 and the heating device 70, respectively, and ride within the camcutouts 120 during rotation of the rotatable cam discs 100 and 110. Inthis regard, rotation of the lever 95 by an operator, through its entirerange of motion, causes corresponding movement of both the movableplaten 110 and the heating device 70 during operation of the beltwelding apparatus 5. To this end, the cam cutouts include cam surfaces135 that provide driving surfaces for the cam followers 125 and 130.Thus, as the rotatable cam discs 100 and 110 are rotated, the camfollowers 125 and 130 ride along the cam surfaces 135 along the pathdefined by the cam cutouts 120 that coordinate to the desired movementof the movable platen 10 and the heating device 70.

In one aspect, a pair of platen cam follower assemblies 125 are mountedon each longitudinal end of the movable platen 10 and a pair of heatingdevice cam follower assemblies 130 are positioned on each longitudinalend of the heating device 70. The cam follower assemblies 125 and 130are preferably roller bearing cam follower assemblies and each include amounting block 215 to mount the cam follower assemblies 125 and 130respectively to the longitudinal ends of the movable platen 10 and theheating device 70. The cam follower assemblies each also include a camfollower roller 220 that is positioned within the cam cutouts 120 and acam follower shaft 225 that connects each cam follower roller 220 to itsmounting block 215. Ball bearings are located at the interface betweenthe cam follower roller 220 and the cam follower shaft 225, so that thecircumferential surface of the cam follower roller 220 can roll alongthe cam surfaces 130.

As described above, first and second cam follower slots 195 and 200 areformed through the end plates 155 and 160 and the cam followers 125 and130 are configured so that the cam follower rollers 220 thereof arepositioned on an outer side of the end plates 155 and 160, within thecam cutouts 120, the mounting blocks 215 are located on an inner side ofthe end plates 155 and 160 and attached to one of the movable platen 10and the heating assembly 70, and the cam follower shafts 225 extendsthrough one of the cam follower slots 195 and 200 to mount the camfollower rollers 220 to the cam follower mounting blocks 215. The camfollower slots 195 and 200 are configured to facilitate the movements ofthe cam followers 125 and 130 during movement of the cam followers 125and 130 along the paths defined by the slots.

In one aspect, the actuator or lever 95 is in the form of a generallytriangular lever that is rotatably coupled at its end to the center ofthe rotatable cam disc 100. A semicircular cutout 240 allows the handleto be in an operative position wherein the handle extends orthogonallyaway from the rotatable cam disc 100, and can be flipped along axis 235to a storage position, wherein the handle 115 extends orthogonallyinward from the lever 95 toward the opposite rotatable cam disc 110 andfits within the handle receiving cutout 240 formed in the end plate 155.In this regard, during transportation of the belt welding apparatus, thehandle 115 can be positioned toward the center of the belt weldingassembly, so that it does not protrude outwardly, to prevent the handle115 from becoming damaged or struck during movement or causingaccidental rotation of the lever 95 during transportation of the beltwelding apparatus 5.

In one aspect, as mentioned previously, one of the platens 10 islaterally movable between a welding position 88, wherein the movableplaten 10 is positioned in close proximity to the stationary platen 15,and a heating position 87 wherein the movable platen 10 is spacedlaterally away from the stationary platen 15 so that a gap 80 is formedbetween the adjacent edges of the platens 10 and 15. The other platen isthe stationary platen 15 and is rigidly secured at both ends to the endplates 155 and 160 so that it remains laterally fixed as the movableplaten 10 moves relative to its fixed orientation.

As mentioned previously, the platens 10 and 15 are preferably elongateplatens with generally flat upper surfaces 25 and 30 that may includestructures for receiving positive drive bars. When mounted at both endsin the horizontal channels 170 on the end plates 155 and 160, the platenupper surfaces 25 and 30 should be substantially horizontally alignedwith one another. In this configuration, when the movable platen 10 isin the loading position, conveyor belt ends 35 and 40 can be positionedon the upper surfaces 25 and 30 with their edges 85 and 90 positioned inend-to-end abutment and being substantially horizontally aligned withone another so that during welding, substantially the entire thicknessof the belt edges 85 and 90 will contact one another, so that the beltedges 85 and 90 are not vertically offset from one another. In oneexample, the platens 10 and 15 are formed from a lightweight materialthat provides rigid support for the belts, for example aluminum.Intermediate supports 161 and 162 are preferably provided for supportingthe platens 10 and 15 along their lengths. One of the intermediatesupports 161 may be adjustable to shift an intermediate portion of themovable platen up or down to configure the platen upper surfaces 25 and30 to be generally coplanar. An actuator is provided for shifting theadjustable intermediate support 161 up and down. The intermediatesupport 161 should have an upper surface formed of a smooth and lowfriction material having good abrasion resistance to facilitate slidingmovement of the movable platen 10 thereover and to reduce wear on theupper surface caused by rubbing between the movable platen 10 and theupper surface during the sliding movement.

Elongate clamping bars 45 and 50 may be positioned above each of theplatens 10 and 15 at laterally inner portions 230 thereof and areconfigured to engage the belt upper surfaces 60 and 65 in closeproximity to the belt edges 85 and 90. A clamp actuator 246 is providedfor urging the clamping bars 45 and 50 toward the belt ends 35 and 40 totightly clamp the belt ends between the clamping bars 45 and 50 and theplaten upper surfaces 60 and 65. In one form, the clamp actuatorincludes a pair of clamp bolts 55 that extend upwardly from each of theplatens at the laterally inside portions 230, and are positionedlongitudinally along the platens to correspond to the positions ofoutwardly open slots 245 at each end of the clamping bars 45 and 50. Soconfigured, with the clamping bars 45 and 50 in their clampingpositions, the outwardly open slots 245 receive the clamp bolts 55.Threaded nuts 250 are coupled to the bolts, and can be tightened oncorresponding threaded portions of the bolts 55 to urge the clampingbars 45 and 50 into tight engagement with the belt upper surfaces 60 and65 above the inside portions 240 of the platens 10 and 15.

Elongate clamping bars 45 and 50 may be positioned above each of theplatens 10 and 15 at laterally inner portions 240 thereof and areconfigured to engage the belt upper surfaces 60 and 65 in closeproximity to the belt edges 85 and 90. A clamp actuator 246 is providedfor urging the clamping bars 45 and 50 toward the belt ends 35 and 40 totightly clamp the belt ends between the clamping bars 45 and 50 and theplaten upper surfaces 60 and 65. In one form, the clamp actuatorincludes a pair of clamp bolts 55 that extend upwardly from each of theplatens at the laterally inside portions 240, and are positionedlongitudinally along the platens to correspond to the positions ofoutwardly open slots 245 at each end of the clamping bars 45 and 50. Soconfigured, with the clamping bars 45 and 50 in their clampingpositions, the outwardly open slots 245 receive the clamp bolts 55.Threaded nuts 250 are coupled to the bolts, and can be tightened oncorresponding threaded portions of the bolts 55 to urge the clampingbars 45 and 50 into tight engagement with the belt upper surfaces 60 and65 above the inside portions 240 of the platens 10 and 15.

So configured, the clamping bars 45 and 50 are in close proximity to thebelt edges 85 and 90 to securely maintain the belt edges in an operativeposition and to restrict the belt ends 35 and 40 from deflecting awayfrom one another during welding of the belt ends 35 and 40 as they areurged toward one another. The clamping bars 45 and 50 may also includebottom elongate spring members in the form of cantilever springs 46 thatextend downward and away from one corner of the clamping bar 45 and 50bottom surfaces in their naturally biased position. In this manner, withthe clamping bars 45 and 50 tightened against the belt surfaces 60 and65, even if the center portion of the clamping bar bows away from thebelt surfaces 60 and 65 during operation due to end portions thereofbeing tightly clumped downwardly by the clamp actuators 246 thecantilever spring portions 46 will tightly engage the upper belt uppersurfaces 60 and 65 with thin edge portions 47 thereof, maintaining theportions of the belt ends 35 and 40, near the edge portions 85 and 90thereof, in tight engagement with the platen upper surfaces 25 and 30during operation of the belt welding apparatus 5 so that the belt ends35 and 40 remain substantially coplanar with eachother.

In one form, the cantilever springs 46 include end portions 48 forengaging the belt ends 35 and 40 that extend laterally inwardly beyondthe clamping bars to engage the belt surfaces with the clamping bars 45and 50 in the clamping position. In this regard, the clamping bars 45and 50 are preferably laterally offset outwardly from platen edgeportions 81 a and 81 b. In this manner, when the heating device 70 israised in the heating position 27, the clamping bars 45 and 50 arepositioned further away from the heating device than the edge portions85 and 90 of the belt ends 35 and 40 so that the clamping bars 45 and 50do not draw a substantial amount of heat away from the belt ends 35 and40. In this manner, a smaller amount of heat is required to be providedto sufficiently melt the materials on the belt ends than would otherwisebe required if the clamping bars 45 and 50 acted as a heat sink to drawheat away from the belt ends. In addition, offsetting the clamping bars45 and 50 away from the heating device 70 reduces the heating of theclamping bars 45 and 50 and the deformation of the clamping bars thatthis may otherwise cause so that the clamping bars effectively provideuniform pressure to clamp the belt ends and maintain them atapproximately coplanar relationship to each other. The clamping bars 45and 50 are preferably formed of a material having a low thermalabsorption to reduce the amount of thermal radiation they absorb. Theclamping bars 45 and 50 are polished to further reduce their radiationabsorption. In one form the clamp bars 45 and 50 predetermined materialhas a low coefficient of thermal expansion to reduce bowing caused bythermal radiation heating an inner edge portion of the clamp bars. Inone example, the predetermined material is stainless steel.

In one aspect, the platen structures in the form of a series of narrowgrooves or recesses 255 extend longitudinally across the platen uppersurfaces 25 and 30 to facilitate use of the belt welding apparatus 5with positive drive belts 265. The platen structures, e.g. recesses 255are sized to receive the ribs 260 of specific positive drive belts 265,and are separated by a longitudinal distance from one another thatcorresponds to the pitch of the positive drive belts 265 that aresupported by the welding apparatus 5. More specifically, the firstrecess 255 of each platen 10 and 15 adjacent to the welding site issized so that the trapezoidal ribs 260 adjacent to the welding site formtight mating fits in the first recesses 255. Upon engaging the clampingbars 45 and 50 against the upper surfaces 60 and 65 of the belt ends 35and 40, the first ribs 260 are locked and tightly held against shiftingin the longitudinal direction of the belts during operation of the beltwelding apparatus 5.

The remaining recesses 255 are sized to provide sufficient clearance fortheir corresponding remaining ribs 260 so that the ribs 260 can beeasily inserted into the recesses 255. In this regard, the belt ends 35and 40 of one or more positive drive belts 265 can be positioned withtheir downwardly extending ribs 260 received in the recesses 255 so thatthe lower surfaces 270 of the belts 265 are positioned flat against theupper surfaces 25 and 30 of the platens 10 and 15. In this manner, thebelt ends 25 and 30 are maintained in their corresponding horizontallyaligned relationship even with their downwardly extending ribs 260, sothat the belt edges 85 and 90 can abut end-to-end across substantiallytheir entire thickness and are not vertically offset from one another.The platens 10 and 15 may include a plurality of sets of groovescorresponding to positive drive belts having different pitches and ribsizes to accommodate more than one type of positive drive belt.

With the belt ends 35 and 40 mounted on the platens 10 and 15 and theplatens in the loading position, the belt ends 35 and 40 are configuredto overhang the platen edge portions 81 a and 81 b. The amount of beltoverhang 37 is typically at least equal to the amount of the belt endsthat will be overlapped and clashed together during belt joining so thatthe belt ends may be joined together without the platens 10 and 15engaging each other and restricting lateral movement of the belt ends 35and 40 toward each other. Preferably, the amount of belt overhang 37 inthe overhang portion is greater than the amount of clash so that duringthe belt heating operation, with the platens belt ends separated fromeach other, the platen edge portions 81 a and 81 b are offset away fromthe heating device 70 further than the belt edges 85 and 90. In thisregard, the amount of heat loss due to heat transferring from the beltends 35 and 40 to the platens 10 and 15 is reduced, while the platens 10and 15 still provide support for the belt ends so that the belt ends donot become vertically offset from one another which could otherwiseresult in a weld being formed with a surface discontinuity.

In one form, the heating device 70 includes an elongate heater 75,coupled to an elongate support bar 275 by heater clamps 280. The supportbar 275 is preferably formed of a rigid material that restrictsdeflection of the support bar 275 thereby preventing deflection orbowing of the elongate heater 75. In this regard, the heater 75 ismaintained in a generally linear orientation extending parallel to thebelt edges 85 and 90. In a preferred form, the heater 75 is anon-contact heater that provides thermal radiation to the belt ends 85and 90 across an air gap since the heater 75 is spaced from the beltends. The preferred infrared heater heats the edges 85 and 90 spacedtherefrom through radiation to restrict melted material sticking to theheater 75. In one aspect, the elongate heater 75 is spaced at generallyequal distance from the belt edges 85 and 90 along their entire lateralwidths. As mentioned, the heater 75 may be coupled to the support bar275 by at least one clamp 280 that receive the heater 75 in snap-fitreception therein to allow removal and replacement of the heater 75 fromthe heating device 70.

In another form, the heating device 70 includes an elongate heatingsupport member 77 that extends longitudinally and the heater 75 ismounted thereto. The heater may include a tubular heat transmissivehousing having a heating filament 356 extending therein. In one form,the infrared bulb may have a generally FIG. 8 configuration with anactive upper tubular housing or bulb 350 and a lower inactive tubularhousing or bulb 355 so that the lower tubular housing 355 may be clampedor held by the support member 77 without interfering with infraredradiation being emitted from the upper bulb tube. The elongate bulbsupport member 77 is preferably formed from a rigid material having alow coefficient of thermal expansion that is slightly greater than thecoefficient of thermal expansion of the bulb tube material. In oneexample, the bulb tube is formed from quartz, having a coefficient ofthermal expansion of about 0.59×10⁻⁶1° C. The bulb support member inthis example is formed of Invar, which has a coefficient of thermalexpansion of about 1.2×10⁻⁶/° C., which is slightly greater than the lowcoefficient of thermal expansion of the quartz bulb member. Because thesupport is spaced from the bulb, even though it has a slightly greatercoefficient of thermal expansion than the bulb, they will deform byabout the same amount during heating operations. In this manner, due thehigh operation temperatures of the infrared bulb during operationthereof, neither the quartz tube, nor the Invar support member 77 willundergo considerable thermal expansion or deformation, to reduce thestress caused by the deformed support on the bulb to avoid damaging orbreaking the quartz material of the bulb. In addition, the elongatesupport member 77 of rigid material provides support to the bulb alongits entire length so that during transportation, if the belt weldingapparatus is roughly treated, the support member will absorb large sheeror impact forces to protect the bulb and restrict the bulb from becomingbroken or damaged. The bulb member is formed of a thermal radiationtransmitting material, e.g. quartz.

The heater 75 may be coated with a gold surface coating 310 that acts toreflect the infrared radiation from the infrared heater to minimize theamount of radiation that is not directed toward the belt ends. Upper andlower portions 365 and 370 are preferably coated with infrared heatresistant material, including a gold coating material. To this end,elongate opposite side edge portions of the bulb may remain uncoated sothat an elongate slot 375 of uncoated material is formed for allowinginfrared heat to pass therethough therefrom. During heating, theuncoated slot portion is preferably positioned adjacent to the belt endsto direct the infrared heat the belt ends while the coating reduces theamount of heat lost and the heating of the other portions of the beltwelder 5. It has been found that in horizontal applications using anon-contact or infrared heating bulb, gravity can result in the filamentbecoming off-centered and located below the horizontal center of theupper bulb portion. Thus, in one form, the elongate uncoated sideportions are offset below the vertical center of the bulb to besubstantially adjacent to the filament to maximize the amount ofinfrared radiation that is directed toward the slots 375 and the beltends 35 and 40 that are positioned adjacent thereto.

In one form, the infrared heater includes an elongate generallycylindrical chamber or tube formed from an infrared radiation conductingmaterial, e.g. quartz. An infrared filament 356 extends within theelongate quartz tube. Spacers are positioned at intervals along tomaintain the filament. Previous bulbs infrared heating bulbs includedimples for maintaining the spacers in position so that the bulbs can beused in vertical applications. However, these dimples have been found tointerfere with the pattern of radiation being emitted from the heater.Thus, in one form the dimples have been removed from the infrared bulbof the present belt welding apparatus so that an inner surface of theinner tube remains has a smooth generally uninterrupted surface alongits longitudinal length. In this manner an even radiation pattern can beapplied to the edges 85 and 90 of the belt ends 35 and 40, without aninterference therealong. The infrared heater quickly heats up, almostinstantaneously to decrease cycle time.

The heating device 70 may also include vertical guiderails 185 that arepositioned at each longitudinal end of the heating device 70 andreceived in the corresponding vertical channels 205 formed in the innersurfaces 175 of the end plates 155 and 160, as described above. Thevertical channels 205 facilitate movement of the heating device 70vertically up and down between the lower stowed position and the raisedheating position of the heating device 70 as described above. However,the configuration of the vertical guiderails 185 within the verticalchannels 205 restricts the heating device 70 from moving in directionsother than vertically up and down, so that when the heating device 70 israised to the heating position, the heater 75 will be configured atsubstantially equal distances from both of the belt ends 85 and 90.

With the lever 95 moved to the belt heating operation position 23 sothat both the heating device 70 and the platen 10 are in a heatingposition, the heater 75 can be activated to provide thermal radiation toheat edges 85 and 90 of the belt ends. In one example, the heater 75 ispreferably in the form of an elongate infrared heater that heats toprovide infrared radiation to the belt ends 35 and 40. During heating ofthe belt ends 35 and 40, the infrared heater 75 generates thermalradiation for a predetermined amount of time, until the belt ends 35 and40 are sufficiently softened for the welding operation. Thepredetermined time is determined based on specific characteristics ofthe belt ends 35 and 40 and the distance between the belt ends and theinfrared heater 75 when both are in the heating positions and the ratingof the heater 75. To this end a timer device 367 is provided forindicating after the predetermined time has elapsed. In one form, thetimer mechanism is configured to turn the heating device 70 off to stopproviding heat to the belt ends after the predetermined time haselapsed.

As discussed above, vertical guiderails 185 are disposed on eachlongitudinal end of the heating device 70 and are received bycorresponding vertical channels 205 on the end plates 155 and 160. Withthe vertical guiderails 185 inserted in the vertical channels 205, theheating device 70 is vertically movable between a lowered stowedposition and a raised heating position. In the lower stowed position,the top of the heating device 70 is preferably positioned verticallybelow the bottom surfaces of the platens 10 and 15, to provide clearancefor the movable platen 10 to move over the heating device 70 into theloading position of the movable platen 10. When the platens arelaterally spaced in their heating position the heating device 70 can beraised vertically between the platens 10 and 15, and more specificallybetween the belt ends 35 and 40 resting thereon, to the heatingposition. In the heating position, the heating device 70, and morespecifically the elongate heater 75 is positioned between the edges 85and 90 of the belt ends 35 and 40 and is generally horizontally coplanarwith the belt ends 35 and 40 to provide generally even heat distributionalong the entire thickness of the belt edges 85 and 90. In the heatingposition, elongate heater 75 is also configured so that it is spaced ata generally uniform distance away from the belt edges 85 and 90 alongthe entire lateral width of the belt ends 35 and 40, providing generallyuniform heat distribution along the entire widths of the belt ends 35and 40.

As mentioned previously, in one aspect, movement of a single actuator orrotatable lever 95 is configured to rotate cam discs 100 and 110 todrive the movement of both the movable platen 10 and the heating device70. In this regard, the movement of the movable platen 10 and heatingdevice 70 to their corresponding operation positions can be carried outsequentially by the programming of the driving mechanism so thatrotation of the lever 95 through its full range moves the movable platenand the heating device 70 relative to one another into their operationpositions at appropriate times during the welding operation rather thanrequiring an operator to separately synchronize the movement of theplatens 10 and 15 and the heating device 70, which increases thedifficulty in operating a welding apparatus and can potentially causethe platens and heating element to interfere with one another throughtheir ranges of motion.

The lever 95 is rotatable along an arcuate pathway with different presetangular positions of the lever 95 along the arcuate pathway (FIG. 2)generally corresponding to different lateral positions of the movableplaten 10 and/or the heating device 70. Positive stops; e.g. ends of thecam path 120, are provided for restricting movement of the lever 95beyond two end portions of the arcuate pathway. In one aspect, the lever95 is rotatable by 180 degrees along the arcuate pathway, whereinspecific angular positions of the lever 95 along the arcuate pathwaycorrespond to specific lateral positions of the movable platen 10 and/orspecific vertical positions of the heating device 70. When the lever 95is positioned at a predetermined intermediate angular position 21 alongthe arc pathway, in a belt loading operation position, the movableplaten 10 is positioned at a predetermined distance away from the fixedplaten 15. In one form the predetermined angular position is at about 15degrees from the belt joining operation position location, which hereinis referred to as the 0 degree location, and the fixed distance is about8 mm. In the furthest rotary direction at one end of its movement alongthe arcuate pathway the lever is in the belt heating operation position23 and the platens are spaced apart and the heater is in a raisedheating position with the belt ends positioned a predetermined distanceaway from the heater. In one form, this is in the 180 degree position.When the lever 95 is moved in the opposite rotary direction, past theintermediate location, and to the furthest angular position it is in thebelt joining operation position 20 and the drive mechanism 210 slidesthe movable platen 10 laterally toward the stationary platen 15 in theirclosest position corresponding to the welding position of the movableplaten 10. In the joining position the belt ends 35 and 40 supported onthe platens 10 and 15 are moved beyond their initial loading positiontoward each other by a predetermined distance to clash and overlap themelted belt ends together. In one form, the belt joining operationposition of the actuator corresponds to the 0 degree position and theplatens are spaced from each other by about 7 mm. While the belt endscan be positioned on the platens in their loading position so that thebelt edge portions 85 and 90 are spaced from one another, preferably thebelt ends abut end-to-end in the loading position. In this manner, whenthe belt ends are moved to the belt joining position 20, the platenshave moved from 8 mm apart to about 7 mm apart to produce about 1 mm ofbelt overlap or clash.

An additional intermediate predetermined rotational position of thelever 95 corresponds to a transition portion of the driving mechanism210, wherein the movable platen 10 reaches its furthest lateral positionaway from the stationary platen 15, at which point the drive mechanismstops movement of the platen 10. In one form, this corresponds to the 90degree position of the lever 95. At this position, the platens 10 and 15define a gap 80 that provides sufficient clearance for the heatingdevice 70 to move vertically upward between the belt ends 35 and 40positioned on the platen upper surfaces 60 and 65. Also at thetransition position, the heating device 70 begins to move verticallyupward from the stowed position within the heating device housing 165toward the heating position. Finally, at the opposite extent of therotation of the lever 95, the heating device 70 reaches its highestvertical position so that the elongate heater 75 is positioned betweenthe belt edges 85 and 90 as described above.

Turning to more of the details, in one example, when viewing the frontface 290 of the rotatable disc 100, the lever 95 is configured to rotateby 180 degrees in a clockwise direction between a 0° position 20corresponding to the lever 95 extending substantially horizontally tothe left and a 180° position 23 corresponding to the lever being rotated180 degrees in the clockwise direction from the 0° position so that thelever 95 extends substantially to the right. At this point, it should benoted that the cam discs 100 and 110 have substantially mirror image camcutouts 120 of one another, such that the movement of the cam discscauses substantially the same movements of the corresponding camfollowers and the movable platen 10 and heating device 70, to ensurethat the platen 10 and heating device 70 are driven uniformly from eachlongitudinal end. The belt loading intermediate operation position 21 ofthe lever 95 is at about 15 degrees. Finally, the transitionintermediate position of the lever 95 is at about the 90 degree position22. With this in mind, reference made herein to movement of camfollowers within the cam cutouts 120 refers generally to the uniformmovement in each of the cam discs 100 and 110.

At the 0° position, the belt welding apparatus 5 is in the weldingconfiguration and the movable platen cam followers 125 engage the firstends 295 of the cam cutouts 120, which act as positive stops,restricting counter-clockwise rotation of the lever 95. This positionrepresents the closest lateral position of the platens 10 and 15relative to one another, corresponding to the welding position, and theheating device 70 is in the lowered stowed position. With the lever 95rotated to the opposite end of its range of motion to 180° position, theheating device cam followers 130 engage the second ends 300 of the camcutouts 120, which act as positive stops, restricting further clockwiserotation of the lever arm 95 and rotatable discs 100 and 110. In thisposition, the movable platen 10 is positioned at its furthest lateraldistance from the stationary platen 15 and the heating device 70 israised to the heating position.

The cam cutouts are generally u-shaped channels in the discs 100 with ashared constant radius portion 340 and changing radius portions 305 and345. In this example, angular rotation of the lever 95, clockwise andcounterclockwise, between the 0° and 180° positions, generallycorresponds to movement of one or both of the movable platen 10 and theheating device 70 relative to the belt welding apparatus 5. Clockwiserotation of the lever 95 from the 0° position initially causes the camsurfaces 135 in the cam cutouts 120, and specifically an increasingradius platen active portion 305 thereof to urge the movable platen camfollowers 125 radially outward along the disc radius from its center ofrotation, which causes the cam followers 125 to urge the movable platen10 laterally away from the stationary platen 15. Specifically, in thisexample, rotation of the lever 95 by about 15 degrees to theintermediate position 21, corresponding to the loading position of thelever 90, moves the movable platen 10 away from the stationary platen 15by a predetermined distance that corresponds to the loading position ofthe movable platen 10. The predetermined distance is determined as thedistance that the platen 10 should move toward stationary platen, beyondtheir loading position to the welding position so that the belts ends 35and 40 are forced against one another by a sufficient amount to allowthe material of the softened belt 35 and 40 after heating to intermixcausing the belt ends 35 and 40 to become fused together upon theirsubsequent cooling. In one example, this distance is approximately 1 mm.On the other hand, the heating device 70 remains stationary during thisportion of the rotation of the lever 95 because the heating device camfollower 130 is within an inactive portion 340 of the cam cutouts 120.

A detent or position lock 310 may be provided to aid the operator indetermining the proper rotation position of the lever 95 into theloading position of the movable platen 10 and also to maintain themovable platen 10 in the loading position as the belts are positioned onthe platen upper surfaces 25 and 30. The position lock 310 includes adetent mechanism or a spring loaded pin 315 that mates with an aperture320 on an inner surface of the rotatable cam disc 100 when the disc isrotated to the loading position. When the position lock is operative andthe disc 100 is rotated to the loading position, the lock aperture 320on the disc inner surface 325 is positioned adjacent to the pin 315 sothat the spring loaded pin 315 is urged under the force of the springinto insertion in the lock aperture 320, restricting rotation of therotatable cam disc 100 from the loading position. In this position, thebelt ends 35 and 40 can be loaded on the platen upper surfaces 25 and 30as described previously. To rotate the rotatable disc 100 from thelocked loading position, a handle 335 of the position lock 310 may begrasped by the user and pulled away from the disc 100 against the forceof the spring and out of its mating engagement with the lock aperture320, allowing the rotatable disc 100 to be rotated.

Another transition operation position 22 of the lever 95, in thisexample about 90 degrees, corresponds to the transition portion whereinthe movable platen cam follower 125 is positioned at the radialoutermost extent of its path in the cam cutout 120 (not shown). At thisposition, the movable platen 10 is positioned in the heating position,at its furthest lateral position away from the stationary platen 15.Thus, because this rotation corresponds to the movable platen camfollower 125 being positioned in an inactive portion 340 of the camcutout 120, further clockwise rotation of the lever 95 will riot causeadditional lateral movement of the movable platen 10. However, at thetransition position, the heating device cam followers 130 will enter thedecreasing radial portion of the cam cutouts 120 so that furtherclockwise rotation will cause the cam surfaces 135 in the cam cutouts120 to urge the heating device cam followers 130 radially inward alongthe rotatable disc 100, causing the heating device 70 to move verticallyupward from the stowed position to the heating position in the gap 80now defined between the laterally spaced platens 10 and 15. Thus, in thetransition position 22, both the cam followers 125 and 130 are in theconstant radius portion. A cam cutout second end portion 300 restrictsrotation of the rotatable disc 100 beyond the 180 degree position.

When the lever 95 is rotated by a predetermined amount in thecounterclockwise rotation direction back to the 0° position from the180° degree heating position, the cam surfaces 135 in the cam cutouts120 act in reverse of that described above so that the heating devicecam followers 130 are urged along the heater active portion 345 radiallyoutward from the disc center of rotation, which urges the heating device70 to correspondingly move vertically downward from its raised heatingposition until it reaches its lowered stowed position at about the 90°degree position of the lever 95. As with the movable platen cam follower125 described previously, when the heating device cam follower 130reaches the constant radius inactive portion 340, furthercounterclockwise rotation of the lever 95 does not cause further radialmovement of the heating device cam follower 130 and thus the heatingdevice 70 remains in its lowered stowed position. However, movementbeyond the 90° transition position in the counterclockwise directioncauses the movable platen cam follower 125 to enter the platen activeportion 305 of the cam cutout 120 so that the movable platen camfollower 125 is urged radially inwardly along the platen active portion305 correspondingly sliding the movable platen 10 toward the stationaryplaten 15, past the loading position, until it reaches the weldingposition, which corresponds to the 0° position of the lever 95. Asmentioned previously, in the welding position, the platens arepositioned closer together than in the loading position so that thebelts that were loaded in end-to-end abutment are clashed together tooverlap by the predetermined distance between the loading and weldingpositions causing the melted material at the edges 85 and 90 of the beltends 35 and 40 to intermix. At this point, a portion of the meltedmaterial will be extruded outwardly from the belt edges, forming amushroom of material surrounding the weld location. The belt ends aremaintained in the welding position where they are allowed to cool, whichwill cause the material of the two belt ends 35 and 40 to fuse, joiningthe belt ends 35 and 40 together.

In one aspect, when the belt welding apparatus 5 is being used to form aweld between the ends of one or more positive drive belts 265 prior toperforming the welding operation, the belt ends 35 and 40 may beprepared by cutting the belt ends to maintain the pitch between the tworibs positioned on either side of the weld site after welding. In thisregard, the welded belt will not have a pitch between ribs at thewelding site that is different than the pitch for the remainder of thebelt. In one example, to maintain the pitch between the ribs at thewelding site, the belt ends should be prepared so that each belt end hasa distance between the edge 85 and 90 of the belt end 35 and 40 and theadjacent rib that is equal to one half the pitch of the positive drivebelt plus one half of the predetermined distance the belt ends areclashed together beyond their in end-to-end abutment loading position.This generates a desired amount of clash or overlap with the excess beltmaterial so that the belt material intermixes and a portion of thematerial is extruded out from between the belts. In this regard, uponwelding of the belts, when the belts are pushed together by thepredetermined distance, the length of each belt end should be decreasedby one half of the predetermined distance as belt ends are pushedtogether. Accordingly, the original pitch between the ribs will beobtained.

To form a uniform pitch a template may be provided for preparing thebelt ends so that with the platens positioned in the belt joiningposition the belt ends have undergone the desired amount of clash and inthe belt heating position the belt ends are spaced by a predetermineddistance from the heating device. In this regard, the template providesan indication to the operator for where the belt end should be cutrelative to an outermost belt drive rib 425 and 430 so that properheating distance and clash will be achieved. Cutting the both of thebelt ends at the proper distance from the outermost drive rib 425 and430 is also important because it maintains the pitch of the conveyorbelt between the drive ribs even at the location of belt welding. In oneform, the template 400 includes an elongate body member 405 formed of astrong material that will preferably retain its shape to provideaccurate cuts. The template has an elongate cutting edge 410 along oneedge thereof. In one form, the template is used to provide square cutslaterally across each of the belt ends along the belt material at apredetermined distance from the closest adjacent drive rib 425 and 430.It should be noted that the template may be configured for more than onebelt. For example, the template maybe configured to provide cuts forconveyor belts with a pitch of about 26 mm and a pitch of about 50 mm.The first groove 415 is used for the 26 mm pitch conveyor belts whilethe second groove 420 is used for the 50 mm pitch belts. In this manner,the outermost drive rib of the 26 mm and 50 mm belts should bepositioned in the corresponding grooves 415 and 420. The predetermineddistance is about half of the pitch of the positive drive belt beingjoined plus about half of the overlap or clash that the belt weldingapparatus 5 is configured to provide between the belt ends, i.e., theextent that the belt ends are overlapped during welding beyondend-to-end abutment. In one example, when a positive drive belt having apitch of about 26 mm is being used, the template is configured to aid informing lateral cuts across each of the belt ends at approximately 13.5mm and the lateral distance between the belt loading position and thebelt joining position is about 1 mm so that about 1 mm of belt overlapis created during welding. In this manner, when the belt ends are weldedso that they overlap by about 1 mm, each belt end 35 and 40 is reducedin length by about 0.5 mm so that the ribs 425 and 430 adjacent to thebelt edge portions 81 and the corresponding formed weld 2 respectivelywill have a pitch of about 26 mm, or the uniform pitch of the positivedrive belt, upon being welded together.

The cutting edge preferably includes a substantially straight edge thatis parallel to the groove 415 or 420 so that a straight cut is madeorthogonally across the lateral width of the belt to ensure that beltends 35 and 40 prepared on the template, when joined, will be properlyoriented to each other with their lateral edges extending in a generallylongitudinal straight line in the lengthwise direction. To use thecutting template 400 a user can place the belt end on a cutting surfacewith the drive ribs extending upwardly. The cutting template ispositioned laterally across the belt with the guide groove 415 or 420positioned over the drive rib 425 or 430 adjacent to the desired cutlocation. With the template 400 in position, the user can either markthe belt at the desired cut location for subsequently making a cut alongthe mark or can cut the belt with the template in place by moving acutting tool along the cutting surface to cut the belt end there along.

In addition, when a belt welding apparatus 5 is used to weld togetherthe ends of one or more positive drive belts 265, the recesses 255 maybe configured to accommodate belts prepared in the above describedmanner by forming the recesses 255 of each of the platens 10 and 15 thatare closest to the gap formed between the platens 10 and 15 to allow thebelts prepared as described above to be positioned end-to-end when theplatens in the loading position and the ribs are inserted in therecesses 255.

To facilitate calibrating the platens 10 and 15 to be properly spaced,one of the platens is a calibrating platen can be released from a secureconnection with the drive mechanism, to become laterally slidable by asmall amount relative to the other platen and the drive mechanism 10. Inthis manner, a user can calibrate the positioning of the platens, byfirst rotating the lever 95 to the welding position. With the drivemechanism 210 in the welding position, a continuous positive drive beltwith the pitch equal to the pitch of the belts that will be used withthe welding apparatus 5 is positioned with its ribs inserted into therecesses of the non-calibrating platen. The calibrating platen can thenbe slid until the ribs 260 over the calibrating platen align with therecesses 255 in the calibrating platen surface. The calibrating platencan then be secured back to the drive mechanism 210. In this manner,when a weld is formed, the pitch between the ribs adjacent to thewelding site should be equal to the pitch in the remainder of thepositive drive belt. Additionally, with the platens 10 and 15calibrated, a user can quickly determine if the ends of a positive drivebelt or belts to be welded together were properly prepared bypositioning the belt ends 35 and 40 with the ribs 260 in the recesseswith the lever 95 in the loading position. In this manner, if the beltends 35 and 40 were properly prepared, the edges 85 and 90 of the beltends 35 and 40 should abut end-to-end in this configuration.

It should be noted that while the movement of the lever 95 has beendescribed herein to refer to particular operative positions of the lever95 and the movable platen 10 and heating device 70, it should beunderstood that the lever 95 provides generally continuous movementbetween and through the operative positions with the exception of theposition lock 310 maintaining the lever arm 95 in the loading positionduring loading of the belt ends 35 and 40 on the platens 10 and 15.

While there have been illustrated and described particular embodimentsof the present invention, it will be appreciated that numerous changesand modifications will occur to those skilled in the art, and it isintended in the appended claims to cover all those changes andmodifications which fall within the true spirit and scope of the presentinvention.

What is claimed is:
 1. A welding apparatus for joining monolithic beltends, the welding apparatus comprising: a frame; a pair of elongateplatens mounted to the frame to be movable laterally relative to eachother in a belt shifting direction and each having structure forreceiving projections of the belt ends to be configured to support thebelt ends and to resist lateral movement of the belt ends thereon; anon-contact heating device having an elongate, infrared heating filamentfor generating thermal radiation and being mounted to the frame to bemovable vertically in a heating device shifting direction between alowered, stowed position generally below the platens and a raised,heating position to be disposed between and spaced from the belt ends;and a user-operable actuator including a rotatable lever operativelycoupled to at least one of the platens and the non-contact heatingdevice so that the same lever is rotatable by a user to at least threedifferent preset operation positions along an arcuate pathway tolaterally move the platens relative to each other in the belt shiftingdirection with the belt ends supported thereon and to vertically movethe heating device in the heating device shifting direction so that theplatens and the heating device shift relative to each other as the leveris rotated along the arcuate pathway to the at least three differentpreset operation positions thereof.
 2. The welding apparatus of claim 1,wherein the at least one platen has a movable mount connected thereto,and the non-contact heating device has a movable mount connectedthereto, and the lever is rotatable to sequentially shift the movablemount for the one platen in the belt shifting direction and the movablemount of the non-contact heating device in the heating device shiftingdirection that is orthogonal to the belt shifting direction.
 3. Thewelding apparatus of claim 1, wherein the lever is configured to berotatable to shift the at least one platen and the non-contact heatingdevice between a belt loading position, the belt end melting position,and a belt end joining position relative to each other.
 4. The weldingapparatus of claim 3, wherein the platens are configured to support thebelt ends to be closely adjacent to or in engagement with each other andthe non-contact heating device is configured to be disposed in a stowedlocation when the at least one platen and the non-contact heating deviceare shifted to the belt loading position by rotation of the lever. 5.The welding apparatus of claim 3, wherein the platens are configured tosupport the belt ends to engage each other and the non-contact heatingdevice is configured to be disposed in a stowed location when the atleast one platen and the non-contact heating device are shifted to thebelt joining position by rotation of the lever.
 6. The welding apparatusof claim 1, wherein the non-contact heating device comprises an infraredheating device having an elongate tubular bulb including an elongatechamber, the elongate filament extending in the elongate chamber, and acoating extending about the tubular bulb so as to leave uncoated sideportions of the bulb in lateral alignment with the filament forrestricting infrared radiation from exiting through the coated portionsso that infrared radiation is generally directed out from the uncoatedside portions of the bulb toward the belt ends.
 7. The welding apparatusof claim 6, wherein the elongate tubular bulb has a substantially smoothgenerally cylindrical inner surface that extends continuously withoutinterruption along the full length of the elongate chamber.
 8. Thewelding apparatus of claim 1, wherein the non-contact heating devicecomprises an infrared heating device including an elongate bulb having apredetermined length for extending the full width of the belt ends,upper and lower portions of the elongate bulb, an infrared filamentextending in the upper portion of the elongate bulb, and a bulb supportthat extends for substantially the predetermined length of the bulbalong and about the lower portion thereof to protect the elongate bulbfrom damage during transport.
 9. The welding apparatus of claim 1,wherein the non-contact heating device comprises an infrared heatingdevice including an elongate bulb and a bulb support in engagementtherewith, the elongate bulb is of a predetermined material having acoefficient of thermal expansion, and the bulb support is of apredetermined material different from the bulb material and has acoefficient of thermal expansion that is slightly greater than thecoefficient of thermal expansion of the bulb material to minimize stresson the elongate bulb from the bulb support during infrared heatingoperations with the infrared heating device.
 10. The welding apparatusof claim 9, wherein the elongate bulb predetermined material has acoefficient of thermal expansion of about 0.59×10-6/° C. and the bulbsupport predetermined material has a coefficient of thermal expansion ofabout 1.2×10-6/° C.
 11. A welding apparatus for joining monolithic beltends, the welding apparatus comprising: a belt support configured tosupport the belt ends in spaced relation to each other; a non-contactheating device for being disposed between and spaced from the belt endsand for generating thermal radiation for welding the belt ends together,wherein the belt support includes a pair of platens having structuresthereof for receiving projections of the belt ends, and a templateconfigured for forming cut belt ends such that with the projectionsthereof received by the platen structures, there is a predeterminedspacing between each of the belt ends and the non-contact heating devicetherebetween.
 12. The welding apparatus of claim 1 wherein the differentpreset operation positions of the lever include a belt loading operationposition with the platens having a first lateral spacing therebetweenand the heating device in the lowered, stowed position, a belt heatingoperation position with the platens having a second lateral spacingtherebetween that is greater than the first lateral spacing and theheating device in the raised, heating position, and a belt joiningoperation position with the platens having a third lateral spacingtherebetween that is less than the first lateral spacing and the heatingdevice in the lowered, stowed position, such that rotation of the leveralong the arcuate pathway from the belt loading operation position tothe belt heating operation position causes the platens to move laterallyapart from one another and the heating device to move verticallyupwardly, and rotation of the lever along the arcuate pathway from thebelt heating operation position to the belt joining operation positioncauses the platens to move laterally toward each other and the heatingdevice to move vertically downwardly.